To protect against damage by the heat emitted through the front-face opening of the lamp housing in a portable lighting fixture, it is customary to provide the lamp housing with a wire grill that registers with the front face. The grill serves to keep heat-vulnerable objects away from the lamp and other hot parts within the lamp housing, and this serves to reduce the chances that such objects will be ignited or damaged by the heat issuing from the housing through its front-face opening. The grill also allows for the flow of air through the region bounded by the grill in front of the front face, thus cooling the light beam emerging through the front-face opening.
A type of situation that presents a severe test for the ability of the grill to prevent fire and/or heat damage is one in which the portable lighting fixture is accidentally tipped over in the direction of its front face onto a horizontal supporting surface and allowed to remain in its tipped-over position for many hours. Prior lighting-fixture grills have kept the front face of the lamp housing spaced from the horizontal supporting surface following such tip-over; but, typically, the lamp housing has been allowed to remain in its initial tipped-over position so that the hot beam emerging from the housing has been aimed directly at the supporting surface, thus subjecting this surface to a significant risk of heat and/or fire damage. This risk can be reduced by increasing the size of the grill, but this makes the fixture bulkier and more costly.
It would be highly desirable if tip-over of the fixture in the direction of its front face onto a horizontal surface could result in reduced heating of the surface as compared to that occurring with a lighting fixture having a conventional grill. It would be especially desirable if such a reduction in heating could be effected without substantially increasing the size of the grill as compared to that of conventional grills used for fixtures of corresponding wattage.